Tuesday, 14 April 2015

Brain teaser of the day

Peter bumped into his old friend Sam whom he hadn't seen for ages.
"So good to see you Sam! It's been years. I've had three children since then. You're very clever; perhaps you can tell me their ages? If you multiply them together, you get 36 and if you add them together the sum will be the number of the house we're standing outside."
"Not enough information," replied Sam.
"Ok here's another clue: my eldest child's just come back from picking flowers."
"I've worked it out," said Sam.

I couldn't do it. Can you?


  1. The only thing I could think of was 2,3,6, added they would come to 11 and look like stalks? 2x3=6, x6=36.

  2. Hi JR - you're on the right track. If you take all the combinations of three numbers which multiply together to make 36. You get:
    36, 1, 1
    18, 2, 1
    9, 2, 2
    If you add the three numbers of each combination together, they all have different totals except for two of them. Therefore the man would be able to see the house number and he would know the answer unless it were one of the two combinations which add up to the same number. Those are 6,6,1 and 9,2,2. The final piece of information was that the eldest child had returned and so the answer must be 9,,2, 2. However, I pointed out to my husband who'd posed this fiendish question, that in the case of 6 year old twins, one would have been born first. In that case would he have said "the elder"? Aargh!

  3. Oh dear.... Don't tell me that you too are burdened/blessed with a mathematician husband? If I had known it was that sort of puzzle, I would have handed it over to him! Actually, I still can. Ha. That'll keep him quiet for a bit.